Evaluation and Comparison of the Dose Received by the Mandible, Maxilla, and Teeth in Two Methods of Three-dimensional Conformal Radiation Therapy and Helical Tomotherapy.

Background: Using three-dimensional conformal radiation treatment (3D-CRT) and helical tomotherapy (HT), this study examines and contrasts the dosage received by the mandible, maxilla, and teeth. Methods: Sixteen patients with head-and-neck cancer (H and NC) were the subject of treatment planning at the Seyyed Al-Shohada Hospital in Isfahan, Iran. This study examined target coverage quality, exposure of healthy tissue, and radiation delivery effectiveness. Results: In terms of a number of measures, including D2%, D50%, Dmean, V95%, conformity index (CI), and homogeneity index (HI) for the planning target volume (PTV) and D2%, D98%, Dmean, V95%, CI, and HI for the nodal PTV, HT showed considerable gains over 3D-CRT. The brainstem, D1cc, and D10cc received considerably lower maximum dosages in HT. Measurements of the right and left cochleas (Dmean, V55, and Dmax) revealed decreases in HT, with Dmean revealing the most significant variations. The Dmean and Dmax values for HT significantly decreased in constrictors as well. In terms of several HT-related indicators, the larynx, optic chiasm, optic nerves, oral cavity, mandible, thyroid, and parotid glands all showed considerable decreases. Conclusion: The findings of the comparison of the two treatment approaches revealed that the HT method was more than 50% more effective than the 3D-CRT method in sustaining organs at risk (OARs) and the target volume dose. In general, dosimetric coverage, homogeneity, conformity indices, and the absence of cold and hot patches showed that HT produced targets with greater accuracy than 3D-CRT. In addition, HT outperformed 3D-CRT in protecting important structures (OARs). HT as a result has the potential to be a more effective method of treatment for those with H and NC and involvement of regional lymph nodes.

Radioprotective Effect of Selenium Nanoparticles: A Mini Review.

Materials and Methods: This study followed the PRISMA reporting guidelines to present the results. A comprehensive search was performed on electronic databases such as PubMed, Scopus, Web of Sciences, and Science Direct. Initially, 413 articles were retrieved. After removing duplicates and applying specific inclusion and exclusion criteria, 10 articles were finally included in this systematic review. Results: The reviewed studies showed that selenium nanoparticles had anti-inflammatory and antioxidant properties. They effectively protected the kidneys, liver, and testicles from damage. Furthermore, there was evidence of efficient radioprotection for the organs examined without significant side effects. Conclusions: This systematic review emphasizes the potential advantages of using selenium nanoparticles to prevent the negative effects of ionizing radiation. Importantly, these protective effects were achieved without causing noticeable side effects. These findings suggest the potential role of selenium nanoparticles as radioprotective agents, offering possible therapeutic applications to reduce the risks related to ionizing radiation exposure in medical imaging and radiotherapy procedures.

The Rationality to Requesting in-ward Magnetic Resonance Imaging Investigation.

Background: Magnetic Resonance imaging (MRI) is a valuable diagnostic tool by its non-invasive/non-ionizing nature. Objective: This study aims to determine justification of MRI in hospitalized patients at a tertiary provincial referent medical center in a one-year period. Material and Methods: In the present retrospective and descriptive cross-sectional study, 438 admitted patients referred for MRI during 2017 were selected using systematic random sampling. The age, gender, investigated organ, the specialty of requesting physician, MRI with and without contrast, MRI diagnostic outcome were collected using checklists. Descriptive statistics and chi-square test were used for data analysis. Results: The mean age of the patients was 42±26 years-old and female represented 53% of enrolled patients. The most and less prevalent investigated organs were the cerebrum and the orbit. After excluding cancer diagnosis, cancer staging, and therapeutic follow-up exams, MRI request was oriented in 64.3% and 77.2% of positive results was concordant with aforementioned diagnostic orientation (P<0.001). Oriented diagnostic MRI requesting is influenced by age, medical specialists and, investigated organ (P<0.001). The positive MRI is influenced significantly by oriented MRI request, gender, medical specialists and investigated organ (P<0.001). The diagnosis concordance of MRI is influenced significantly by oriented MRI request, medical specialists and investigated organ (P<0.001). Conclusion: Appropriate implementation of medical imaging requires boosting employed rationality by the concerned physicians. The current suboptimal results to requesting MRI rationality should mandate supplementary educational programs as to incite the medical corpus more closely implementing the published medical practice guidelines.

Chitosan-Imidazolium Core-Shell Nanoparticles of Gd-Mn-Mo Polyoxometalate as Novel Potential MRI Nano-Agent for Breast Cancer Detection.

Polyoxometalates (POMs) are mineral nanoclusters with many advantages in various diagnostic fields, in particular cancer detection. This study aimed to synthesize and evaluate the performance of gadolinium-manganese-molybdenum polyoxometalate (Gd-Mn-Mo; POM) nanoparticles coated with chitosan-imidazolium (POM@CSIm NPs) for detecting 4T1 breast cancer cells by magnetic resonance imaging in vitro and in vivo. The POM@Cs-Im NPs were fabricated and characterized by FTIR, ICP-OES, CHNS, UV-visible, XRD, VSM, DLS, Zeta potential, and SEM. Cytotoxicity, cellular uptake, and MR imaging in vivo and in vitro of L929 and 4T1 cells were also assessed. The efficacy of nanoclusters was demonstrated using MR images of BALB/C mice bearing a 4T1 tumor in vivo. The evaluation of the in vitro cytotoxicity of the designed NPs showed their high biocompatibility. In fluorescence imaging and flow cytometry, NPs had a higher uptake rate by 4T1 than L929 (p < 0.05). Furthermore, NPs significantly increased the signal strength of MR images, and its relaxivity (r1) was calculated as 4.71 mM-1 s-1. MR imaging also confirmed the attachment of nanoclusters to cancer cells and their selective accumulation in the tumor region. Overall, the results showed that fabricated POM@CSIm NPs have considerable potential as an MR imaging nano-agent for early 4T1 cancer detection.

Binary Logistic Regression Modeling of Voice Impairment and Voice Assessment in Iranian Patients with Nonlaryngeal Head-and-Neck Cancers after Chemoradiation Therapy: Objective and Subjective Voice Evaluation.

Background: Laryngeal damages after chemoradiation therapy (RT) in nonlaryngeal head-and-neck cancers (HNCs) can cause voice disorders and finally reduce the patient's quality of life (QOL). The aim of this study was to evaluate voice and predict laryngeal damages using statistical binary logistic regression (BLR) models in patients with nonlaryngeal HNCs. Methods: This cross-section experimental study was performed on seventy patients (46 males, 24 females) with an average age of 50.43 ± 16.54 years, with nonlaryngeal HNCs and eighty individuals with assumed normal voices. Subjective and objective voice assessment was carried out in three stages including before, at the end, and 6 months after treatment. Eventually, the Enter method of the BLR was used to measure the odds ratio of independent variables. Results: In objective evaluation, the acoustic parameters except for F0 increased significantly (P < 0.001) at the end treatment stage and decreased 6 months after treatment. The same trend can be seen in the subjective evaluations, whereas none of the values returned to pretreatment levels. Statistical models of BLR showed that chemotherapy (P < 0.05), mean laryngeal dose (P < 0.05), V50 Gy (P = 0.002), and gender (P = 0.008) had the greatest effect on incidence laryngeal damages. The model based on acoustic analysis had the highest percentage accuracy of 84.3%, sensitivity of 87.2%, and the area under the curve of 0.927. Conclusions: Voice evaluation and the use of BLR models to determine important factors were the optimum methods to reduce laryngeal damages and maintain the patient's QOL.

A review of bismuth-based nanoparticles and their applications in radiosensitising and dose enhancement for cancer radiation therapy.

About 50% of cancer patients receive radiation therapy. Despite the therapeutic benefits of this method, the toxicity of radiation in the normal tissues is unavoidable To improve the quality of radiation therapy, in addition to other methods such as IMRT, IGRT, and high radiation dose, nanoparticles have shown excellent potential when ionising radiation is applied to the target volume. Recently, bismuth-based nanoparticles (BiNPs) have become particularly popular in radiation therapy due to their high atomic numbers (Z), high X-ray attenuation coefficient, low toxicity, and low cost. Moreover, it is easy to synthesise in a variety of sizes and shapes. This study aimed to review the effects of the bismuth-based NP and its combination with other compounds, and their potential synergies in radiotherapy, discussed based on their physical, chemical, and biological interactions. Targeted and non-targeted bismuth-based NPs used in radiotherapy as radiosensitizers and dose enhancement effects are described. The results reported in the literature were categorised into various groups. Also, this review has highlighted the importance of bismuth-based NPs in different forms of cancer treatment to find the highest efficiency for applying them as a suitable candidate for various cancer therapy and future clinical applications.

Recent Metal Nanotheranostics for Cancer Diagnosis and Therapy: A Review.

In recent years, there has been an increasing interest in using nanoparticles in the medical sciences. Today, metal nanoparticles have many applications in medicine for tumor visualization, drug delivery, and early diagnosis, with different modalities such as X-ray imaging, computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), etc., and treatment with radiation. This paper reviews recent findings of recent metal nanotheranostics in medical imaging and therapy. The study offers some critical insights into using different types of metal nanoparticles in medicine for cancer detection and treatment purposes. The data of this review study were gathered from multiple scientific citation websites such as Google Scholar, PubMed, Scopus, and Web of Science up through the end of January 2023. In the literature, many metal nanoparticles are used for medical applications. However, due to their high abundance, low price, and high performance for visualization and treatment, nanoparticles such as gold, bismuth, tungsten, tantalum, ytterbium, gadolinium, silver, iron, platinum, and lead have been investigated in this review study. This paper has highlighted the importance of gold, gadolinium, and iron-based metal nanoparticles in different forms for tumor visualization and treatment in medical applications due to their ease of functionalization, low toxicity, and superior biocompatibility.

Diagnostic Performance Evaluation of Multiparametric Magnetic Resonance Imaging in the Detection of Prostate Cancer with Supervised Machine Learning Methods.

Prostate cancer is the second leading cause of cancer-related death in men. Its early and correct diagnosis is of particular importance to controlling and preventing the disease from spreading to other tissues. Artificial intelligence and machine learning have effectively detected and graded several cancers, in particular prostate cancer. The purpose of this review is to show the diagnostic performance (accuracy and area under the curve) of supervised machine learning algorithms in detecting prostate cancer using multiparametric MRI. A comparison was made between the performances of different supervised machine-learning methods. This review study was performed on the recent literature sourced from scientific citation websites such as Google Scholar, PubMed, Scopus, and Web of Science up to the end of January 2023. The findings of this review reveal that supervised machine learning techniques have good performance with high accuracy and area under the curve for prostate cancer diagnosis and prediction using multiparametric MR imaging. Among supervised machine learning methods, deep learning, random forest, and logistic regression algorithms appear to have the best performance.

Novel MR imaging nanoprobe for hepatocellular carcinoma detection based on manganese-zinc ferrite nanoparticles: in vitro and in vivo assessments.

PURPOSE: Achieving new contrast enhancer agents that can produce high-resolution images in magnetic resonance imaging (MRI) with a minimum dose and side effects has always been important. METHODS: Herein, the pegylated curcumin-coated manganese-zinc ferrite nanoparticles (MZF@CA-PEG-CUR NPs) have been reported as an MR imaging nanoprobe in hepatocellular carcinoma detection in the murine model for the first time. In vitro studies were done on HEPA 1-6 cancer cells and L929 as normal cells, and in vivo studies were done on hepatocellular carcinoma (HCC) using xenograft models of HCC. RESULTS: The prepared NP had a diameter of 105 nm with narrow size distribution and was superparamagnetic with a saturated magnetization (Ms) of 39 emu/g. The NP was biocompatible without any significant hemolysis and cytotoxicity. Prussian blue staining showed more cellular uptake of HEPA 1-6 compared to L929 control cells after incubation (P < 0.05). The concentration of Fe in mice blood confirmed the plasma half-life of about 3 h; it seems the PEGylation increased the circulation time. ICP-OES of Fe showed the highest tumor localization for MZF@CA-CUR-PEG NPs, due to passive accumulation, compared to the other mice studied organs. The r2 relaxivity of NPs was 134.89 mM- 1 s- 1, and in vitro MRI demonstrated better effects in HEPA 1-6 cells than in L929 (P < 0.05). Also, in vivo MR images showed signal enhancement efficacy in tumor-bearing mice. CONCLUSION: This study demonstrated that the MZF@CA-CUR-PEG nanoprobe could be a promising candidate as an MR imaging agent in hepatocellular carcinoma early detection.

Radiation Exposure and Lifetime Attributable Risk of Cancer Incidence and Mortality from Low- and Standard-Dose CT Chest: Implications for COVID-19 Pneumonia Subjects.

Since the novel coronavirus disease 2019 (COVID-19) outbreak, there has been an unprecedented increase in the acquisition of chest computed tomography (CT) scans. Nearly 616 million people have been infected by COVID-19 worldwide to date, of whom many were subjected to CT scanning. CT exposes the patients to hazardous ionizing radiation, which can damage the genetic material in the cells, leading to stochastic health effects in the form of heritable genetic mutations and increased cancer risk. These probabilistic, long-term carcinogenic effects of radiation can be seen over a lifetime and may sometimes take several decades to manifest. This review briefly describes what is known about the health effects of radiation, the lowest dose for which there exists compelling evidence about increased radiation-induced cancer risk and the evidence regarding this risk at typical CT doses. The lifetime attributable risk (LAR) of cancer from low- and standard-dose chest CT scans performed in COVID-19 subjects is also discussed along with the projected number of future cancers that could be related to chest CT scans performed during the COVID-19 pandemic. The LAR of cancer Incidence from chest CT has also been compared with those from other radiation sources, daily life risks and lifetime baseline risk.

Advanced Magnetic Resonance Imaging Modalities for Breast Cancer Diagnosis: An Overview of Recent Findings and Perspectives.

Breast cancer is the most prevalent cancer among women and the leading cause of death. Diffusion-weighted imaging (DWI) and diffusion tensor imaging (DTI) are advanced magnetic resonance imaging (MRI) procedures that are widely used in the diagnostic and treatment evaluation of breast cancer. This review article describes the characteristics of new MRI methods and reviews recent findings on breast cancer diagnosis. This review study was performed on the literature sourced from scientific citation websites such as Google Scholar, PubMed, and Web of Science until July 2021. All relevant works published on the mentioned scientific citation websites were investigated. Because of the propensity of malignancies to limit diffusion, DWI can improve MRI diagnostic specificity. Diffusion tensor imaging gives additional information about diffusion directionality and anisotropy over traditional DWI. Recent findings showed that DWI and DTI and their characteristics may facilitate earlier and more accurate diagnosis, followed by better treatment. Overall, with the development of instruments and novel MRI modalities, it may be possible to diagnose breast cancer more effectively in the early stages.

Assessment of Oxaliplatin-Loaded Iodine Nanoparticles for Chemoradiotherapy of Human Colorectal Cancer (HT-29) Cells.

Colorectal cancer is highly prevalent worldwide and has significant morbidity and mortality in humans. High-atomic-number nanoparticles such as iodine can act as X-rays absorbers to increase the local dose. The synthesis and fabrication of oxaliplatin-loaded iodine nanoparticles, their characterization, cell toxicity, radiosensitivity, cell apoptosis, and cell cycle assay in human colorectal cancer (HT-29) cells are investigated. Results show that the synthesis of a new iodine nanoparticle, polymerized triiodobenzene coated with chitosan and combined with oxaliplatin as a chemotherapeutic drug, performed well in vitro in an intracellular radiosensitizer as chemoradiotherapy agent in HT-29 cell lines. Findings also show that the INPs alone have no impact on cell cycle development and apoptosis. In contrast, oxaliplatin-loaded INPs along with 2 and 6 MV radiation doses produced more apoptosis. The interaction of INPs with mega-voltage photon energies is the cause of a major radiosensitization enhancement in comparison to radiation alone. Furthermore, results show that INPs may work as radiosensitization nanoprobe agents in the treatment of HT-29 cells due to their effect on increasing radiation dose absorption. Overall, iodine nanoparticles may be used in the treatment of colorectal cancers in clinical studies.

Iron oxide nanoparticles coated with polydopamine as a potential nano-photothermal agent for treatment of melanoma cancer: an in vivo study.

Melanoma is a metastatic cancer resistant to a wide range of therapies, including standard chemotherapy and radiation therapy, and cannot be treated with existing treatments owing to its intrinsic drug resistance. In terms of convenience and cheap cost of fabrication, one of the novel treatments is using polydopamine-coated iron oxide nanoparticles (IONs@PDA). Iron oxide nanoparticles (IONs) were synthesized (7.36 nm) and coated with polydopamine (15-20 nm). To examine the effect of photothermal ablation in melanoma cells (B16-F10), a Q-switched ruby laser (λ = 694 nm, spot size = 4 mm, output power = 5 J/s) was used. The prepared nanoprobe was applied to mice, and their survival after treatment was evaluated. Then histopathological studies were done on the livers and skins of the treated mice. The nanoparticles absorb the laser, raising the temperature and initiating photothermal treatment, with significant apoptosis (74%) after the 4th time of treatment. Photothermal therapy (PTT) by using IONs@PDA proved to be effective in the treatment of melanoma cells (tumor size of < 2 mm) without side effects. The lifespan of mice was significantly increased in a group of mice post-administered IONs@PDA and laser ablation. The fabricated nanoprobe (IONs@PDA) enhanced the melanoma cell apoptosis in the mice model, and it has promise for the treatment of melanoma (B16-F10) cells using photothermal therapy.

COVID-19 and MERS: Are their Chest X-ray and Computed Tomography Scanning Signs Related?

Background: COVID-19 is a respiratory infection brought about by SARS-COV-2. Most of the patients contaminated by this pathogen are afflicted by respiratory syndrome with multiple stages ranging from mild upper respiratory involvement to severe dyspnea and acute respiratory distress syndrome cases. Keeping in mind the high sensitivity of computed tomography (CT) scan in detecting abnormalities, it became the number one modality in COVID-19 diagnosis. A wide diversity of CT features can be found in COVID-19 cases, which can be observed before the onset of clinical signs. The review article is aimed to highlight recent discrepancies in CT-scan and chest X-ray (CXR) characteristics between COVID-19 and Middle East Respiratory Syndrome (MERS). Method: This review study was performed in the literature from the beginning of COVID-19 until the middle of April 2021. For this reason, all relevant works through scientific citation websites such as Google Scholar, PubMed, and Web of Science have been investigated in the mentioned period. Results: COVID-19 was more reproductive than MERS, while MERS was significantly higher in terms of mortality rate (COVID-19: 2.3% and MERS: 34.4%). Signs of ground-glass opacity (GGO), peripheral consolidation, and GGO accompanying with consolidation are the same signs CXR in both MERS and COVID-19. Indeed, fever, cough, headache, and sore throat are the most symptoms in all studied patients. Conclusion: Both COVID-19 and MERS have the same imaging signs. The most similar chest CT findings are GGO, peripheral consolidation, and GGO superimposed by consolidation in both studied diseases, and no statistical differences were seen among the mean number of chest CT-scans in MERS and COVID-19 cases.

Determining the optimum tumor control probability model in radiotherapy of glioblastoma multiforme using magnetic resonance imaging data pre- and post- radiation therapy.

Background: Glioblastoma multiforme (GBM) is the most common and malignant brain tumor. The current standard of care is surgery followed by radiation therapy (RT). Radiotherapy treatment plan evaluation relies on radiobiological models for accurate estimation of tumor control probability (TCP). This study aimed to assess the impact of obtained magnetic resonance imaging (MRI) data before and 12 weeks after RT to achieve the optimum TCP model to improve dose prescriptions in radiation therapy of GBM. Materials and Methods: In this quasi-experimental study, MR images and its relevant data from 30 patients consisting of 9 females and 21 males (mean age of 46.3 ± 15.8 years) diagnosed with GBM, whose referred for radiotherapy were selected. The data of age, gender, tumor size, volume, and signal intensity using analysis of MRI data pre- and postradiotherapy were used for calculating TCP. TCP was calculated from three common radiobiological models including Poisson, linear quadratic, and equivalent uniform dose. The impact of some radiobiological parameters on final TCP in all patients planned with three-dimensional conformal radiation therapy was obtained. Results: A statistically significant difference was found among TCP in Poisson model compared to the other two models (P < 0.001). Changes in tumor volume and size after treatment were statistically significant (P < 0.05). Different combinations of radiobiological parameters (α/ß and SF2 in all models) observed were meaningful (P < 0.05). Conclusion: The results showed that among TCP radiobiological models, the optimum is the Poisson. The results also identified the importance of TCP radiobiological models in order to improve radiotherapy dose prescriptions.

Recent nanotheranostics applications for cancer therapy and diagnosis: A review.

Nanotheranostics has attracted much attention due to its widespread application in molecular imaging and cancer therapy. Molecular imaging using nanoparticles has attracted special attention in the diagnosis of cancer at early stages. With the progress made in nanotheranostics, studying drug release, accumulation in the target tissue, biodistribution, and treatment effectiveness are other important factors. However, according to the studies conducted in this regard, each nanoparticle has some advantages and limitations that should be examined and then used in clinical applications. The main goal of this review is to explore the recent advancements in nanotheranostics for cancer therapy and diagnosis. Then, it is attempted to present recent studies on nanotheranostics used as a contrast agent in various imaging modalities and a platform for cancer therapy.

Investigation of fetal absorbed dose in V/Q scan in three trimesters of pregnancy using Monte Carlo simulation.

The ventilation/perfusion (V/Q) single-photon emission computed tomography is the first method of diagnosis for pulmonary embolism in pregnant women. This study aimed to calculate the fetal absorbed dose and compare to recommended values in V/Q scan at three trimesters of pregnancy by Monte Carlo simulation (code MCNPX) using simulated phantoms, based on the adult female MIRD phantom. The collection of pregnant women phantoms (that of Stabin) was designed with changes in the MIRD phantom. Source organs were defined for each of the radiopharmaceuticals used in two scans, 133Xe and 81mKr for the lung and bladder and technetium diethylene-triamine-pentaacetate (99mTc-DTPA) aerosol for lung ventilation scan. Also, technetium macroaggregated albumin (99mTc-MAA) for lung ventilation scan, lung, bladder, and liver. Fetal absorbed dose was calculated and evaluated for the administration radiopharmaceuticals using the MCNP simulation output. For 200 MBq 99mTc-MAA, fetal absorbed dose was 1.01-1.97 mGy, which is higher than the values recommended by International Commission on Radiological Protection (ICRP). The same fetal absorbed dose was found for activities of 54 and 70 MBq in the third trimester. For 99mTc-DTPA-aerosol, fetal absorbed dose as a ventilation tracer was within the permitted range. For 133Xe and 81mKr, it was negligible. It is concluded that the fetus received the highest absorbed dose in the third trimester of pregnancy. For this reason, in this period of pregnancy, it is recommended to use the lower administration activity and her awareness must be done.

The Radioprotective Effect of Ascorbic Acid and Kefir against Genotoxicity Induced by Exposure in Mice Blood Lymphocytes.

The aim of this research was to determine how coadministration of ascorbic acid prior to the beginning of X-irradiation influences the lymphocyte DNA damage and also if the kefir supplementation to irradiated mice may alter the recovery procedure of lymphocyte genetic material injury. Following treatment of animals with these agents, the whole-body of mice were irradiated to 6 MV X-rays, then genotoxicity activity was investigated by comet assay. Our results show that the Total Comet Score (TCS) value was 1.39 and 1.5 fold less in the kefir and ascorbic acid groups respectively the following irradiation than in the irradiated mice only. Coadministration of ascorbic acid and kefir with 2 h, before relatively to 2 Gy radiation decreased DNA damage in lymphocyte blood cells. The antioxidant strength of ascorbic acid and kefir were investigated by the study of the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging properties and also ferric reducing antioxidant power (FRAP) assay. Our results revealed that ascorbic acid and kefir show strong antioxidant activity by these methods. According to these results, it seems that ascorbic acid and kefir, as a free radical scavenging capacitiy, protect animal lymphocyte blood cells from radiation-induced DNA injury and genotoxicity.

Synthesis and Application of Fe3O4@Au Composite Nanoparticles as Magnetic Resonance/Computed Tomography Dual-Modality Contrast Agent.

BACKGROUND: None of the molecular imaging modalities can produce imaging with both anatomical and functional information. In recent years, to overcome these limitations multimodality molecular imaging or combination of two imaging modalities can provide anatomical and pathological information. METHODS: Magnetic iron oxide nanoparticles were prepared by co-precipitation method and then were coated with silica according to Stober method. Consequently, silica-coated nanoparticles were amino-functionalized. Finally, gold nanoparticles assembled onto the surfaces of the previous product. Cytotoxicity effects of prepared Fe3O4@Au nanoparticles were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay on human hepatocellular carcinoma cells. Their ability as a dual-mode contrast agent was investigated by magnetic resonance (MR) and computed tomography (CT) imaging. RESULTS: Fe3O4@Au nanoparticles were spherical undersize of 75 nm. X-ray diffraction analysis confirmed the formation of Fe3O4@Au nanoparticles. The magnetometry result confirmed the superparamagnetism property of prepared nanoparticles, and the saturation magnetization (Ms) was found to be 33 emu/g. Fe3O4@Au nanoparticles showed good cytocompatibility up to 60 µg/mL. The results showed that the Fe3O4@Au nanoparticles have good r2 relaxivity (135.26 mM-1s-1) and good X-ray attenuation property. CONCLUSION: These findings represent that prepared Fe3O4@Au nanoparticles in an easy and relatively low-cost manner have promising potential as a novel contrast agent for dual-modality of MR/CT imaging.

Optimal scheduling of the nanoparticle-mediated cancer photo-thermo-radiotherapy.

Maximal synergistic effect between photothermal therapy and radiotherapy (RT) may be achieved when the interval between these two modalities is optimal. In this study, we tried to determine the optimal schedule of the combined regime of RT and nano-photothermal therapy (NPTT), based on the cell cycle distribution and kinetics of cell death. To this end, alginate-coated iron oxide-gold core-shell nanoparticles (Fe3O4@Au/Alg NPs) were synthesized, characterized, and their photo-radio sensitization potency was evaluated on human nasopharyngeal cancer KB cells. Our results demonstrated that synthesized NPs have a good potential in radiotherapy and near-infrared (NIR) photothermal therapy. However, results from flow cytometry analysis indicated that a major portion of KB cells were accumulated in the most radiosensitive phases of cell cycle (G2/M) 24 h after NPTT. Moreover, the maximal synergistic anticancer efficacy (12.3% cell viability) was observed when RT was applied 24 h following the administration of NPTT (NPs [30 µg/mL, 4 h incubation time] + Laser [808 nm, 1 W/cm2, 5 min] + RT [6 Gy]). It is noteworthy that apoptosis was the dominant cell death pathway in the group of cells treated by combination of NPTT and RT. This highly synergistic anticancer efficacy provides a mechanistic basis for Fe3O4@Au/Alg NPs-mediated photothermal therapy combined with RT. Knowing such a basis is helpful to promote novel nanotechnology cancer treatment strategies.